Magnetic Response of Surface Plasmons in Ag75Co25 Non-Solid Solution Films

Abstract

The magnetic response of surface plasmon polaritons (SPPs) has the potential to be utilized as a magnetic sensor. To this end, a non-solid solution material (Ag-Co system) was selected for evaluation, as such materials are expected to efficiently excite the SPPs, while also highly increasing the magnetic sensitivity with a single layer. In the Ag-Co non-solid solution film, Ag is a good SPP excitation material, whereas Co is a ferromagnetic material. The excitation and magnetic response of the SPPs in Ag-Co single layer films were investigated by varying the film thickness and wavelength, from which it was found that the optimal characteristics for both were obtained with films 35-50 nm thick. The largest magnetic response of the SPPs, as defined by the ratio of reflectivity change under the applied magnetic field between zero and 400 mT, was determined as ~0.29. The Ag-Co non-solid solution system therefore represents a good material for obtaining a large magnetic response of SPPs.

Magnetic response of surface plasmon polaritons in silver / Co2FeSi0.6Al0.4Heusler alloy / silver films

“…The maximum values of absolute magnetic activity |R| max measured at 500 and 700 nm show 0.11 and 0.14, respectively. The maximum values of absolute magnetic activity |R| max of 0.14 is not so high compared with previous reports [5,6]. One of the methods to increase the |R| max is to adjust the each layer thickness because it can improve plasmonic properties of the film.…”

“…The magnetic response of SPP, which is called magneto-plasmonic effect, has been reported using films combined a noble metal with a ferromagnetic material [1][2][3][4][5][6]. Although halfmetallic ferromagnetic materials, such as Heusler alloys, are paid attention to spintronic devices because of their high spin polarization [7,8], their magneto-plasmonic effect has not been reported yet.…”

Annealing temperature dependence of Ag–Co single layer films on magneto-plasmonic effect

“…The geometry is Voigt configuration in cyclotron resonance-inactive mode, in which applied magnetic field is parallel to the plane of incidence and perpendicular to the propagation direction of the SPPs. The magneto-plasmonic effect was evaluated from the reflectivity curves obtained from the ATR measurement on the basis of the normalized reflectivity change in a magnetic field using the following formula 9,12,14,30,31) [ ( )-( )] ( )…”

“…Magneto-plasmonic effect is a promising phenomenon connected surface plasmonic properties with magnetic properties [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] for a future magnetic sensing application. [19][20][21][22][23][24] The surface plasmon polaritons (SPPs), which are electromagnetic waves propagating at an interface between a metal and a dielectric material, are super-sensitive to changes in the dielectric constants of the interfacial materials.…”

“…Three types of magneto-plasmonic materials have been reported as follows; (1) all metallic tri-layer or multilayer films of a noble metal/a magnetic metal/a noble metal, such as Au/Co/Au, 1,4,5) Ag/Co/Ag, 2,18) Au/Fe/Au, 3,7) Ag/CoFeAlSi/Ag films 14) and so on, (2) a magnetic ceramic/a noble metal bilayer film, such as Au/MFe 2 O 4 (M=Zn, Ni, Co) 10,12,13) and Ag/Bi 3 Fe 5 O 12 films, 17) and (3) single layer films with binary non-solid-solution metals, [25][26][27][28] such as Ag-Co, 9,11,16) Ag-Fe, 11) and Ag-Ni films. 15) The excitation condition of the SPPs is strongly related to the thicknesses of whole and each metallic layers, so it is difficult to control magnetic and plasmonic properties independently in all metallic tri-layer or multilayer films.…”